JP6896694B2 - Mask blank, phase shift mask, phase shift mask manufacturing method and semiconductor device manufacturing method - Google Patents

Description

The present invention relates to a mask blank and a phase shift mask manufactured by using the mask blank. The present invention also relates to a method for manufacturing a semiconductor device using the above-mentioned phase shift mask.

Generally, in the manufacturing process of a semiconductor device, a fine pattern is formed by using a photolithography method. In addition, a number of substrates called transfer masks are usually used to form this fine pattern. In order to miniaturize the pattern of a semiconductor device, it is necessary to shorten the wavelength of the exposure light source used in photolithography in addition to miniaturizing the mask pattern formed on the transfer mask. In recent years, the wavelength of an exposure light source for manufacturing a semiconductor device has been shortened from a KrF excimer laser (wavelength 248 nm) to an ArF excimer laser (wavelength 193 nm).

As a type of transfer mask, a halftone type phase shift mask is known in addition to a binary mask having a light-shielding pattern made of a chrome-based material on a conventional translucent substrate. A molybdenum silicide (MoSi) -based material is widely used for the phase shift film of the halftone type phase shift mask.

In recent years, it has been studied to apply a Si-based material such as SiN or SION, which is a material having high ArF light resistance, to the phase shift film. Si-based materials tend to have lower light-shielding performance than MoSi-based materials, and have been relatively difficult to apply to a phase-shift film having a transmittance of less than 10%, which has been widely used in the past. On the other hand, the Si-based material is easy to apply to a phase shift film having a relatively high transmittance of 10% or more (Patent Document 1).
On the other hand, in the halftone type phase shift mask, when the phase shift mask is set in the exposure apparatus and irradiated with ArF exposure light, there is a problem that the pattern of the phase shift film is displaced. This is due to the fact that the ArF exposure light absorbed inside the pattern of the phase shift film is converted into heat energy, and the heat is transferred to the translucent substrate to cause thermal expansion (Patent Document 2).

JP-A-2015-11246 JP-A-2015-152924

The phase shift film of a halftone type phase shift mask (hereinafter, simply referred to as a phase shift mask) has a function of transmitting exposure light at a predetermined transmittance and its phase with respect to the exposure light transmitted through the phase shift film. It is also necessary to have a function of causing a predetermined phase difference with the exposure light passing through the air by the same distance as the thickness of the shift film. Recently, the miniaturization of semiconductor devices has further progressed, and the application of exposure technology such as multiple patterning technology has begun. The requirements for overlay accuracy between each transfer mask of the transfer mask set used for manufacturing one semiconductor device are becoming more stringent. Therefore, even in the case of the phase shift mask, there is an increasing demand for suppressing the thermal expansion of the pattern of the phase shift film (phase shift pattern) and suppressing the movement of the phase shift pattern due to this.

In Patent Document 2, the back surface reflectance (reflectance on the translucent substrate side) of the thin film pattern when the photomask is set in the exposure apparatus and is irradiated with the exposure light from the translucent substrate side is higher than before. doing. By making the backside reflectance higher than before, let's reduce the heat that is converted by the thin film absorbing the light energy of the exposure light, and suppress the occurrence of misalignment of the thin film pattern due to thermal expansion of the translucent substrate. It is supposed to be. Then, as a mask blank for manufacturing a binary mask, we propose a structure in which a highly reflective substance layer and a light blocking layer are laminated in this order on a translucent substrate. Further, as a mask blank for manufacturing a phase shift mask, we propose a structure in which a highly reflective substance layer and a phase inversion layer are laminated in this order on a translucent substrate.

In the case of a mask blank for manufacturing a binary mask, the laminated structure of the highly reflective substance layer and the light blocking layer is required to have a predetermined light shielding performance. This is not difficult. On the other hand, in the case of a mask blank for manufacturing a phase shift mask, the laminated structure of the highly reflective material layer and the phase inversion layer has a function of transmitting at a predetermined transmittance with respect to the exposure light, and also with respect to the transmitted exposure light. It is required to have a function of causing a predetermined phase difference with the exposure light that has passed through the air by the same thickness as the laminated structure. The feasible variation is limited in the phase shift film of the design concept that secures a predetermined back surface reflectance only by the highly reflective material layer. In particular, when a phase shift film having a relatively high transmittance (for example, 15% or more) is examined based on a design concept that relies on a highly reflective material layer, the laminated structure of the highly reflective material layer and the phase inversion layer has a predetermined transmittance. When the phase difference is set to a predetermined value, it is unavoidable that the back surface transmittance is lowered, and it becomes difficult to suppress the misalignment of the phase shift pattern.

Therefore, the present invention has been made to solve the conventional problems, and is a function of transmitting ArF exposure light with a predetermined transmittance in a mask blank provided with a phase shift film on a translucent substrate. It also has a function of causing a predetermined phase difference with respect to the transmitted ArF exposure light, suppresses thermal expansion of the phase shift film pattern (phase shift pattern), and suppresses the movement of the phase shift pattern due to this. It is an object of the present invention to provide a mask blank having a possible phase shift film. Another object of the present invention is to provide a phase shift mask manufactured by using this mask blank. An object of the present invention is to provide a method for manufacturing a semiconductor device using such a phase shift mask.

In order to achieve the above object, the present invention has the following configuration.
(Structure 1)
A mask blank having a phase shift film on a translucent substrate.
The phase shift film has a function of transmitting the exposure light of the ArF excimer laser with a transmittance of 15% or more, and the exposure light transmitted through the phase shift film in the air by the same distance as the thickness of the phase shift film. It has a function of causing a phase difference of 150 degrees or more and 210 degrees or less with the exposure light that has passed through.
The phase shift film is formed of a material containing a non-metal element and silicon.
The phase shift film includes a structure in which a first layer, a second layer, and a third layer are laminated in this order from the translucent substrate side.
When the refractive indexes of the first layer, the second layer, and the third layer at the wavelength of the exposure light are n ₁ , n ₂ , and n ₃ , respectively, the relationship of n ₁ > n ₂ and n ₂ <n _3. The filling,
When the extinction coefficients of the first layer, the second layer, and the third layer at the wavelength of the exposure light are k ₁ , k ₂ , and k ₃ , respectively, k ₁ > k ₂ and k ₂ <k ₃ . Meet the relationship,
A mask blank characterized in that the relationship of 0.5 ≦ d ₁ / d ₃ <1 is satisfied when the film thicknesses of the first layer and the third layer are d ₁ and d _{3, respectively.}

(Structure 2)
When the film thickness of the second layer is d ₂ , and the total film thickness of the three layers of the first layer, the second layer, and the third layer is d _T , 0.24 ≦ d ₂ / d _T ≦ The mask blank according to the configuration 1, wherein the mask blank satisfies the relationship of 0.3.
(Structure 3)
The mask blank according to the configuration 1 or 2, wherein the first layer has a refractive index n ₁ of 2.3 or more and an extinction coefficient k _{1 of 0.2 or more.}

(Structure 4)
The mask blank according to any one of configurations 1 to 3, wherein the second layer has a refractive index n ₂ of 1.7 or more and an extinction coefficient k _{2 of 0.01 or more.} ..
(Structure 5)
The mask blank according to any one of configurations 1 to 4, wherein the third layer has a refractive index n ₃ of 2.3 or more and an extinction coefficient k _{3 of 0.2 or more.} ..

(Structure 6)
The phase shift film according to any one of configurations 1 to 5, wherein the phase shift film is formed of a material composed of a non-metal element and silicon, or a material composed of a metalloid element, a non-metal element and silicon. Mask blank.
(Structure 7)
The mask blank according to any one of configurations 1 to 6, wherein the first layer, the second layer, and the third layer are all made of a material containing nitrogen.

(Structure 8)
The mask blank according to any one of configurations 1 to 7, wherein the second layer is formed of a material containing oxygen.
(Structure 9)
The mask blank according to any one of configurations 1 to 8, wherein a light-shielding film is provided on the phase shift film.

(Structure 10)
A mask blank having a phase shift film having a transfer pattern on a translucent substrate.
The phase shift film has a function of transmitting the exposure light of the ArF excimer laser with a transmittance of 15% or more, and the exposure light transmitted through the phase shift film in the air by the same distance as the thickness of the phase shift film. It has a function of causing a phase difference of 150 degrees or more and 210 degrees or less with the exposure light that has passed through.
The phase shift film is formed of a material containing a non-metal element and silicon.
The phase shift film includes a structure in which a first layer, a second layer, and a third layer are laminated in this order from the translucent substrate side.
When the refractive indexes of the first layer, the second layer, and the third layer at the wavelength of the exposure light are n ₁ , n ₂ , and n ₃ , respectively, the relationship of n ₁ > n ₂ and n ₂ <n _3. The filling,
When the extinction coefficients of the first layer, the second layer, and the third layer at the wavelength of the exposure light are k ₁ , k ₂ , and k ₃ , respectively, k ₁ > k ₂ and k ₂ <k ₃ . Meet the relationship,
A phase shift mask characterized in that the relationship of 0.5 ≦ d ₁ / d ₃ <1 is satisfied when the film thicknesses of the first layer and the third layer are d ₁ and d _{3, respectively.}
(Structure 11)
When the film thickness of the second layer is d ₂ , and the total film thickness of the three layers of the first layer, the second layer, and the third layer is d _T , 0.24 ≦ d ₂ / d _T ≦ The phase shift mask according to the configuration 10, wherein the phase shift mask satisfies the relationship of 0.3.

(Structure 12)
The phase shift mask according to the configuration 10 or 11, wherein the first layer has a refractive index n ₁ of 2.3 or more and an extinction coefficient k _{1 of 0.2 or more.}
(Structure 13)
The phase shift according to any one of configurations 10 to 12, wherein the second layer has a refractive index n ₂ of 1.7 or more and an extinction coefficient k _{2 of 0.01 or more.} mask.

(Structure 14)
The phase shift according to any one of configurations 10 to 13, wherein the third layer has a refractive index n ₃ of 2.3 or more and an extinction coefficient k _{3 of 0.2 or more.} mask.
(Structure 15)
The phase shift film according to any one of configurations 10 to 14, characterized in that the phase shift film is formed of a material composed of a non-metal element and silicon, or a material composed of a metalloid element, a non-metal element and silicon. Phase shift mask.

(Structure 16)
The phase shift mask according to any one of configurations 10 to 15, wherein the first layer, the second layer, and the third layer are all made of a material containing nitrogen.
(Structure 17)
The phase shift mask according to any one of configurations 10 to 16, wherein the second layer is made of a material containing oxygen.

(Structure 18)
The phase shift mask according to any one of configurations 10 to 17, wherein a light-shielding film having a pattern including a light-shielding band is provided on the phase-shift film.
(Structure 19)
A method for manufacturing a phase shift mask using the mask blank according to the configuration 9.
The process of forming a transfer pattern on the light-shielding film by dry etching and
A step of forming a transfer pattern on the phase shift film by dry etching using a light-shielding film having the transfer pattern as a mask, and
A method for manufacturing a phase shift mask, which comprises a step of forming a pattern including a light-shielding band on the light-shielding film by dry etching using a resist film having a pattern including a light-shielding band as a mask.
(Structure 20)
A method for manufacturing a semiconductor device, which comprises a step of exposing and transferring a transfer pattern to a resist film on a semiconductor substrate using the phase shift mask according to the configuration 18.

The mask blank of the present invention includes a phase shift film on a translucent substrate, and the phase shift film has a function of transmitting with a predetermined transmittance to ArF exposure light and for the transmitted ArF exposure light. It also has a function of generating a predetermined phase difference, can suppress thermal expansion of the pattern of the phase shift film (phase shift pattern), and can suppress the movement of the phase shift pattern due to this.

It is sectional drawing which shows the structure of the mask blank in 1st Embodiment of this invention. It is sectional drawing which shows the manufacturing process of the phase shift mask in 1st Embodiment of this invention. It is a graph which shows the relationship between _{the film thickness ratio (d 1} / d ₃ ) of the 1st layer and the 3rd layer in a phase shift film, and the absorption rate A. It is a graph which shows the relationship between _{the film thickness ratio (d 2} / d _T ) of the 2nd layer and the whole film thickness in the phase shift film, and the absorption rate A.

Hereinafter, embodiments of the present invention will be described. The inventors of the present application have described a means for suppressing a pattern misalignment due to thermal expansion while having a function of transmitting ArF exposure light at a predetermined transmittance and a function of generating a predetermined phase difference in a phase shift film. Diligent research was conducted.
In order to suppress the displacement of the pattern due to thermal expansion, it is necessary to suppress the conversion of ArF exposure light into thermal energy inside the phase shift film. The inventor of the present application has found that the temperature rise of the phase shift film is substantially proportional to the square of the ratio of ArF exposure light absorbed inside the phase shift film (Absorption rate A of ArF exposure light). Then, based on this finding, when the ArF exposure light incident on the translucent substrate is taken as 100%, the absorption rate A of the ArF exposure light can be reduced to 60% or less inside the phase shift film described above. It was found that it is important to suppress the conversion to thermal energy in the permissible range. Absorption rate A, transmittance T, and backside reflectance R of ArF exposure light in the phase shift film (this backside reflectance R is ArF exposure incident on the translucent substrate from the interface between air and the translucent substrate. The backside reflectance when the amount of light is 100%. The same shall apply hereinafter.) "A [%] = 100 [%]-(transmittance T [%] + backside reflectance R) [%]) ”Relationship holds. Therefore, in order to satisfy the predetermined transmittance T and the absorption rate A of 60% or less, it is important to increase the back surface reflectance R to some extent.

In order to increase the backside reflectance R of the phase shift film provided on the translucent substrate, at least the layer of the phase shift film in contact with the translucent substrate should be formed of a material having a high extinction coefficient k at the exposure wavelength. You will need it. The phase shift film having a single-layer structure is generally formed of a material having a large refractive index n and a small extinction coefficient k because of the required optical characteristics and the need to satisfy the film thickness. Here, it is considered that the back surface reflectance R of the phase shift film is increased by adjusting the composition of the material forming the phase shift film to significantly increase the extinction coefficient k. When this adjustment is performed, the phase shift film cannot satisfy the condition of the transmittance T in a predetermined range, so that it becomes necessary to significantly reduce the thickness of the phase shift film. However, this time, by reducing the thickness of the phase shift film, the phase shift film cannot satisfy the condition of the phase difference in a predetermined range. Since there is a limit to increasing the refractive index n of the material forming the phase shift film, it is difficult to increase the back surface reflectance R in the phase shift film having a single layer structure. In the case of a phase shift film having a relatively high transmittance of 15% or more, it is particularly difficult to increase the back surface reflectance R with a phase shift film having a single layer structure.

On the other hand, in the case of a phase shift film having a two-layer structure, it is possible to adjust so as to increase the back surface reflectance R while satisfying the conditions of the transmittance T in the predetermined range and the phase difference in the predetermined range, but the design is free. The degree is not so high. In particular, when a phase shift film having a predetermined phase difference (150 degrees or more and 210 degrees or less) and an optical characteristic of a transmittance of 15% or more is realized in a two-layer structure, the back surface reflectance R is sufficient. It is difficult to increase the absorption rate A, and it is difficult to reduce the absorption rate A to 60% or less. Therefore, in the case of a phase-shift film made of a silicon-based material (a material containing a non-metal element and silicon) and having a laminated structure of three or more layers, it is possible to realize that the above conditions can be satisfied at the same time. went. In the case of a phase shift film having such a laminated structure of three or more layers, it is possible to adjust so as to increase the back surface reflectance R while satisfying the conditions of the transmittance T in a predetermined range and the phase difference in a predetermined range. Not only is there a high degree of design freedom.

As a result, in order to satisfy the above conditions at the same time, as a phase shift film containing a structure in which the first layer, the second layer, and the third layer are laminated in this order, the refractive index n and the extinction coefficient of each of the three layers are obtained. We have found that k only needs to satisfy a specific relationship. Specifically, in order to realize a phase shift film that simultaneously satisfies the three conditions of a predetermined phase difference (150 degrees or more and 210 degrees or less), a transmittance T of 15% or more, and an absorption rate A of 60% or less. When the refractive indexes of the ArF exposure light of the first layer, the second layer, and the third layer at the wavelengths are n ₁ , n ₂ , and n ₃ , respectively, the relationship of n ₁ > n ₂ and n ₂ <n _{3 is satisfied.} Further, when the extinction coefficients at the wavelengths of the ArF exposure light of the first layer, the second layer, and the third layer are k ₁ , k ₂ , and k ₃ , respectively, k ₁ > k ₂ and k ₂ <k ₃ . We have found that a phase shift film that satisfies the relationship should be used.

_{Here, the inventors of the present application have described the ratio of the film thicknesses d 1} and d ₃ of the first layer and the third layer in the phase shift film _{(the ratio of the film thickness d 1} of the first layer to the film _{thickness d 3} of the third layer). Focusing on the relationship between the film thickness ratio d ₁ / d ₃ ) and the absorptivity A, an optical simulation was performed on the phase shift film. Specifically, first, the refractive index n and the extinction coefficient k of the first layer, the second layer, and the third layer of the phase shift film were set to values satisfying the above-mentioned specific relationship. Next, the first layer, the thickness of the second layer and the third layer d _1, to adjust the d _2, d _3, was designed phase shift film to be a desired transmittance and phase difference. Further, an optical simulation was performed with the parameters of the designed phase shift film, and the absorptivity A of the _{designed phase shift film having a film thickness ratio d 1} / d _{3 was calculated.} The value of the absorption rate A was calculated using the above-mentioned relational expression A [%] = 100 [%]-(transmittance T [%] + backside reflectance R [%]). _{Subsequently, the film thicknesses d 1} and d ₃ of the first layer and the third layer of the designed phase shift film were increased or decreased to design a phase shift film having each film thickness _{ratio d 1} / d _3. Further, the same optical simulation was performed to calculate the absorption rate A of the phase shift film at _{each film thickness ratio d 1} / d _3. Incidentally, by increasing or decreasing the thickness d _1, d _3, the transmittance and phase difference of the phase shift film in some cases deviate relatively greatly from a desired value. In this case, _{by changing the film thickness d 2} , the transmittance and the phase difference of the phase shift film are brought close to desired values.

FIG. 3 is a graph showing the relationship between _{the film thickness ratio d 1} / d ₃ of the first layer and the third layer and the absorption rate A in the phase shift film obtained as a result of such an optical simulation. As shown in the figure, in order to realize a phase shift film that simultaneously satisfies the three conditions of a predetermined phase difference (150 degrees or more and 210 degrees or less), a transmittance T of 15% or more, and an absorption rate A of 60% or less. The inventors of the present application have found that the relationship of 0.5 ≦ d ₁ / d _{3 <1 must be satisfied.}

Further, the inventors of the present application have defined a film thickness ratio of the film _{thickness d 2 of the second layer in the phase shift film and the total film thickness d T} of the three layers of the first layer, the second layer and the third layer (three layers). We also paid attention to the relationship between the _{film thickness ratio d 2} / d _T ), which is the ratio of the film _{thickness d 2} of the second layer to the total film thickness d _{T), and the absorption rate A.} Then, an optical simulation was performed on the phase shift film in the same manner as described above in the description of FIG. _{FIG. 4 shows the film thickness d 2} of the second layer in the phase shift film _{and the total film thickness d T} of the three layers of the first layer, the second layer, and the third layer obtained as a result of such an optical simulation. It is a graph which shows the relationship between the film thickness ratio d ₂ / d _{T and the absorption rate A.} As shown in the figure, in order to realize a phase shift film that simultaneously satisfies the three conditions of a predetermined phase difference (150 degrees or more and 210 degrees or less), a transmittance T of 15% or more, and an absorption rate A of 60% or less. The inventors of the present application have found that the relationship of 0.24 ≦ d ₂ / d _{T ≦ 0.3 must be satisfied.} The present invention has been made as a result of the above diligent studies.

FIG. 1 is a cross-sectional view showing the configuration of the mask blank 100 according to the embodiment of the present invention. The mask blank 100 of the present invention shown in FIG. 1 has a structure in which a phase shift film 2, a light shielding film 3, and a hard mask film 4 are laminated in this order on a translucent substrate 1.

The translucent substrate 1 can be formed of, in addition to synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, low thermal expansion glass (SiO _2- TiO ₂ glass, etc.) and the like. Among these, synthetic quartz glass has a high transmittance for ArF excimer laser light and is particularly preferable as a material for forming the translucent substrate 1 of a mask blank. The refractive index n at the wavelength (about 193 nm) of the ArF exposure light of the material forming the translucent substrate 1 is preferably 1.5 or more and 1.6 or less, and 1.52 or more and 1.59 or less. More preferably, it is 1.54 or more and 1.58 or less.

The phase shift film 2 preferably has a transmittance T of 15% or more with respect to ArF exposure light. Since the phase shift film 2 of the first embodiment has a high degree of freedom in design, even when the transmittance T is 15% or more, the back surface reflectance R is increased while satisfying the condition of the phase difference in a predetermined range. Can be adjusted as follows. The transmittance T of the phase shift film 2 with respect to the exposure light is preferably 16% or more, and more preferably 17% or more. On the other hand, as the transmittance T of the phase shift film 2 with respect to the exposure light increases, it becomes difficult to increase the back surface reflectance R. Therefore, the transmittance T of the phase shift film 2 with respect to the exposure light is preferably 40% or less, and more preferably 35% or less.

In order to obtain an appropriate phase shift effect, the phase shift film 2 has a phase difference of 150 between the transmitted ArF exposure light and the light that has passed through the air by the same distance as the thickness of the phase shift film 2. It is required to be adjusted so as to be in the range of degree or more and 210 degrees or less. The phase difference in the phase shift film 2 is preferably 155 degrees or more, and more preferably 160 degrees or more. On the other hand, the phase difference in the phase shift film 2 is preferably 200 degrees or less, and more preferably 195 degrees or less.

The phase shift film 2 is transparent in a state where only the phase shift film 2 is present on the translucent substrate 1 from the viewpoint of reducing the ratio of ArF exposure light incident on the inside of the phase shift film 2 to be converted into heat. When the ArF exposure light incident on the optical substrate 1 is 100%, the reflectance (backside reflectance) R of the translucent substrate 1 side (back surface side) with respect to the ArF exposure light is at least 20% or more. Is required. The state in which only the phase shift film 2 exists on the translucent substrate 1 means that when the phase shift mask 200 (see FIG. 2 (g)) is manufactured from the mask blank 100, a light shielding pattern is formed on the phase shift pattern 2a. It refers to a state in which 3b is not laminated (a region of a phase shift pattern 2a in which the shading pattern 3b is not laminated). On the other hand, if the back surface reflectance R is too high in the presence of only the phase shift film 2, the phase shift mask 200 manufactured from the mask blank 100 is used to transfer to an object to be transferred (resist film on a semiconductor wafer, etc.). When the exposure transfer is performed, the reflected light on the back surface side of the phase shift film 2 has a large influence on the exposure transfer image, which is not preferable. From this viewpoint, the back surface reflectance R of the phase shift film 2 with respect to the ArF exposure light is preferably 40% or less.

The phase shift film 2 in the present embodiment has a structure in which the first layer 21, the second layer 22, and the third layer 23 are laminated from the translucent substrate 1 side. The entire phase shift film 2 needs to satisfy at least the above-mentioned conditions of transmittance T, phase difference, and backside reflectance R. _{In order to satisfy the above conditions, the phase shift film 2 in the present embodiment has n 1} , n ₂ , and n refractive indexes at the wavelengths of the ArF exposure light of the first layer 21, the second layer 22, and the third layer 23, respectively. _{When 3} , _{the relationship of n 1} > n ₂ and n ₂ <n ₃ is satisfied, and the extinction coefficients of the first layer 21, the second layer 22, and the third layer 23 at the wavelengths of the ArF exposure light are k ₁ , respectively. When k ₂ and k ₃ , _{the relationship of k 1} > k ₂ and k ₂ <k ₃ is satisfied, and when the film thicknesses of the first layer 21 and the third layer 23 are d ₁ and d ₃ , respectively, 0. It is configured to satisfy the relationship of 5 ≦ d ₁ / d _{3 <1.} Further, in the phase shift film 2 in the present embodiment, the film thickness of the second layer 22 is d ₂ , and the total film thickness of the three layers of the first layer 21, the second layer 22 and the third layer 23 is d _T. When, it is configured to satisfy the relationship of 0.24 ≦ d ₂ / d _{T ≦ 0.3.}

On that basis, the refractive index n ₁ of the first layer 21 is preferably 2.3 or more, and more preferably 2.4 or more. _{The refractive index n 1} of the first layer 21 is preferably 3.0 or less, and more preferably 2.8 or less. _{The extinction coefficient k 1} of the first layer 21 is preferably 0.2 or more, and more preferably 0.25 or more. Further, the extinction coefficient k ₁ of the first layer 21 is preferably 0.5 or less, and more preferably 0.4 or less. The refractive index n ₁ and the extinction coefficient k ₁ of the first layer 21 are numerical values derived by regarding the entire first layer 21 as one optically uniform layer.

The refractive index n ₂ of the second layer 22 is preferably 1.7 or more, and preferably 1.8 or more. Further, the refractive index n ₂ of the second layer 22 is preferably less than 2.3, more preferably 2.2 or less. _{The extinction coefficient k 2} of the second layer 22 is preferably 0.01 or more, and more preferably 0.02 or more. The extinction coefficient k ₂ of the second layer 22 is preferably 0.15 or less, and more preferably 0.13 or less. The refractive index n ₂ and the extinction coefficient k ₂ of the second layer 22 are numerical values derived by regarding the entire second layer 22 as one optically uniform layer.

_{The refractive index n 3} of the third layer 23 is preferably 2.3 or more, and preferably 2.4 or more. _{The refractive index n 3} of the third layer 23 is preferably 3.0 or less, and more preferably 2.8 or less. _{The extinction coefficient k 3} of the third layer 23 is preferably 0.2 or more, and more preferably 0.25 or more. _{The extinction coefficient k 3} of the third layer 23 is preferably 0.5 or less, and more preferably 0.4 or less. The refractive index n ₃ and the extinction coefficient k ₃ of the third layer 23 are numerical values derived by regarding the entire third layer 23 as one optically uniform layer.

The refractive index n and the extinction coefficient k of the thin film including the phase shift film 2 are not determined only by the composition of the thin film. The film density and crystal state of the thin film are also factors that influence the refractive index n and the extinction coefficient k. Therefore, various conditions for forming a thin film by reactive sputtering are adjusted so that the thin film has a desired refractive index n and extinction coefficient k. In order to make the first layer 21, the second layer 22, and the third layer 23 within the range of the above-mentioned refractive index n and extinction coefficient k, a noble gas and a reactive gas (when forming a film by reactive sputtering, a noble gas and a reactive gas ( It is not limited to adjusting the ratio of mixed gas (oxygen gas, nitrogen gas, etc.). There are various positional relationships such as the pressure in the film forming chamber when forming a film by reactive sputtering, the electric power applied to the sputtering target, and the distance between the target and the translucent substrate 1. These film forming conditions are unique to the film forming apparatus, and are appropriately adjusted so that the formed first layer 21, second layer 22, and third layer 23 have a desired refractive index n and extinction coefficient k. Is to be done.

The phase shift film 2 (first layer 21, second layer 22 and third layer 23) is formed of a material containing a non-metal element and silicon. A thin film formed of a material containing silicon and a transition metal tends to have a high extinction coefficient k. In order to reduce the overall thickness of the phase shift film 2, the phase shift film 2 may be formed of a material containing a non-metal element, silicon, and a transition metal. Examples of the transition metal contained in this case include molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), chromium (Cr), hafnium (Hf), nickel (Ni), and vanadium (V). ), Zirconium (Zr), ruthenium (Ru), rhodium (Rh), zinc (Zn), niobium (Nb), palladium (Pd) and the like, or an alloy of these metals. On the other hand, the phase shift film 2 is preferably formed of a material composed of a non-metal element and silicon, or a material composed of a metalloid element, a non-metal element and silicon. When the phase shift film 2 is required to have high light resistance to ArF exposure light, it is preferable that the phase shift film 2 does not contain a transition metal. Further, in this case, it is desirable not to include metal elements other than transition metals because it cannot be denied that they may cause a decrease in light resistance to ArF exposure light.

When the phase shift film 2 contains a metalloid element, if one or more metalloid elements selected from boron, germanium, antimony and tellurium are contained, the conductivity of silicon used as a sputtering target can be expected to increase. preferable.
When the phase shift film 2 contains a non-metal element, it is preferable to contain one or more non-metal elements selected from nitrogen, carbon, fluorine and hydrogen. The non-metallic elements also include noble gases such as helium (He), argon (Ar), krypton (Kr) and xenon (Xe). Further, it is preferable that the first layer 21, the second layer 22, and the third layer 23 of the phase shift film 2 are all made of a material containing nitrogen. In general, a thin film formed by adding nitrogen to the same material as the thin film tends to have a larger refractive index n than a thin film formed without containing nitrogen. A higher refractive index n of any of the first layer 21, the second layer 22, and the third layer 23 of the phase shift film 2 is required to secure a predetermined phase difference required for the phase shift film 2. The overall film thickness can be reduced. Further, when nitrogen is contained in any of the first layer 21, the second layer 22, and the third layer 23 of the phase shift film 2, oxidation of the side wall of the pattern when the phase shift pattern is formed can be suppressed.

The first layer 21 is preferably formed in contact with the surface of the translucent substrate 1. By configuring the first layer 21 in contact with the surface of the translucent substrate 1, the back surface reflectance generated by the laminated structure of the first layer 21, the second layer 22, and the third layer 23 of the phase shift film 2 described above. This is because the effect of increasing R can be obtained more. If the effect of increasing the back surface reflectance R of the phase shift film 2 is small, an etching stopper film may be provided between the translucent substrate 1 and the phase shift film 2.
The film thickness d ₁ of the first layer 21 is preferably 30 nm or less, and more preferably 25 nm or less. Further, particularly considering that the back surface reflectance R of the phase shift film 2 is increased, the film thickness d ₁ of the first layer 21 is preferably 15 nm or more, and more preferably 17 nm or more.

The first layer 21 is preferably not actively contained with oxygen (the oxygen content is preferably 3 atomic% or less when the composition is analyzed by X-ray photoelectron spectroscopy or the like, and is detected. It is more preferable that it is equal to or less than the lower limit value). _{The decrease in the extinction coefficient k 1} of the first layer 21 caused by the inclusion of oxygen in the material forming the first layer 21 is larger than that of other non-metal elements, and the back surface reflectance R of the phase shift film 2 is increased. This is because it drops significantly.

_{The refractive index n 1} of the first layer 21 is larger than _{the refractive index n 2} of the second layer 22 _{(n 1} > n _{2 ), and the extinction coefficient k 1} of the first layer 21 is the extinction coefficient of the second layer 22. It is required that the coefficient is larger than _{k 2 (k 1} > k _2). Therefore, the nitrogen content in the material forming the first layer 21 is preferably 40 atomic% or more, more preferably 45 atomic% or more, and further preferably 50 atomic% or more. However, the nitrogen content in the material forming the first layer 21 is preferably 57 atomic% or less. _{When the nitrogen content is higher than the nitrogen content (about 57 atomic%) of Si 3} N ₄ , which is stoichiometrically stable, the first layer is caused by heat generated in the first layer 21 during dry etching, mask cleaning, and the like. Nitrogen is easily released from 21 and the nitrogen content is likely to decrease.

Unlike the first layer 21, the second layer 22 is preferably formed of a material containing oxygen.
Further, the second layer 22 may be formed of a material composed of silicon, nitrogen, and oxygen, or a material composed of one or more elements selected from non-metal elements and metalloid elements, silicon, nitrogen, and oxygen. preferable. _{The second layer 22 has the smallest refractive index n 2} and extinction coefficient k ₂ among the three layers constituting the phase shift film 2, and the refractive index n increases as the oxygen content in the material increases. _{This is because 2} tends to decrease, and the degree of decrease in the extinction coefficient k ₂ also tends to be larger than that of nitrogen. The oxygen content of the material formed by the second layer 22 is preferably 20 atomic% or more, more preferably 25 atomic% or more, and further preferably 30 atomic% or more. On the other hand, as the oxygen content in the second layer 22 increases, the entire phase shift film 2 required to secure a predetermined transmittance T and a phase difference with respect to the ArF exposure light in the entire phase shift film 2 The total film thickness d _{T of} is getting thicker. Considering these points, the oxygen content of the material forming the second layer 22 is preferably 60 atomic% or less, more preferably 55 atomic% or less, and further preferably 50 atomic% or less.
Further, the nitrogen content in the material forming the second layer 22 is preferably smaller than the nitrogen content in the material forming the first layer 21 and the third layer 23. Therefore, the nitrogen content in the material forming the second layer 22 is preferably 5 atomic% or more, and more preferably 10 atomic% or more. The nitrogen content in the material forming the second layer 22 is preferably 40 atomic% or less, more preferably 35 atomic% or less, and further preferably 30 atomic% or less.

As described above, the second layer 22 has the smallest refractive index n ₂ and extinction coefficient k ₂ among the three layers constituting the phase shift film 2. If the film thickness d ₂ of the second layer 22 becomes too thick, the total film thickness d _T of the entire phase shift film 2 becomes thick. In this respect, the film thickness d ₂ of the second layer 22 is preferably 30 nm or less, more preferably 25 nm or less, and further preferably 22 nm or less. Further, if the film thickness d ₂ of the second layer 22 is too thin, the reflection of the exposure light at the interface between the second layer 22 and the third layer 23 is lowered, and the back surface reflectance R of the phase shift film 2 is lowered. There is a fear. In this respect, the film thickness d ₂ of the second layer 22 is preferably 10 nm or more, more preferably 15 nm or more, and further preferably 16 nm or more.

Like the first layer 21, the third layer 23 is preferably not actively contained with oxygen (the oxygen content is 3 atomic% when the composition is analyzed by X-ray photoelectron spectroscopy or the like. It is preferably less than or equal to, and more preferably less than or equal to the lower limit of detection).
As described above, the refractive index n ₃ of the third layer 23 is larger than _{the refractive index n 2} of the second layer 22 _{(n 2} <n ₃ ), and the extinction coefficient k ₃ of the third layer 23 is the second. greater than the extinction coefficient _{k 2} of the layer 22 _(k 2 <k ₃₎ is determined. Therefore, the nitrogen content in the material forming the third layer 23 is preferably 40 atomic% or more, more preferably 45 atomic% or more, and further preferably 50 atomic% or more. However, the nitrogen content in the material forming the third layer 23 is preferably 57 atomic% or less. _{When the nitrogen content is higher than the nitrogen content (about 57 atomic%) of Si 3} N ₄ , which is stoichiometrically stable, the third layer is caused by heat generated in the third layer 23 during dry etching, mask cleaning, and the like. Nitrogen is easily released from 23, and the nitrogen content is likely to decrease.
Like the first layer 21, the third layer 23 has a higher refractive index n ₃ and an extinction coefficient k ₃ than the second layer 22. When the thickness d ₃ of the third layer 23 is too thick, in order to predetermined transmittance T in the entire phase shift film 2, the thickness d ₁ of the other of the first layer 21 and second layer 22, Since d ₂ must be thinned, the back surface reflectance R of the phase shift film 2 may decrease. In this respect, the film thickness d ₃ of the third layer 23 is preferably 50 nm or less, more preferably 40 nm or less, and further preferably 35 nm or less. Further, the third layer 23 has a refractive index n ₃ and an extinction coefficient k ₃ higher than those of the second layer 22, and has a film thickness d of a certain degree or more in order to increase the back surface reflectance R of the phase shift film 2. ₃ is required. In this respect, the film thickness d ₃ of the third layer 23 is preferably 15 nm or more, and more preferably 25 nm or more.

As described above, the film thickness ratio d ₁ / d ₃ of the first layer 21 and the third layer 23 is preferably 0.5 or more, more preferably 0.52 or more, and 0.55 or more. Is more preferable. _{Further, the film thickness ratio d 1} / d ₃ of the first layer 21 and the third layer 23 is preferably less than 1, more preferably 0.99 or less, and further preferably 0.95 or less.
Further, the film thickness ratio d ₂ / d _{T of the total film thickness d T} of the second layer 22 and the three layers from the first layer 21 to the third layer 23 is preferably 0.24 or more, preferably 0.245 or more. Is more preferable, and 0.25 or more is further preferable. Further, the film thickness ratio d ₂ / d _{T of the total film thickness d T} of the second layer 22 and the three layers from the first layer 21 to the third layer 23 is preferably 0.3 or less, preferably 0.295 or less. Is more preferable, and 0.29 or less is further preferable.

The first layer 21, the second layer 22, and the third layer 23 in the phase shift film 2 are formed by sputtering, but any sputtering such as DC sputtering, RF sputtering, and ion beam sputtering can be applied. Considering the film formation rate, it is preferable to apply DC sputtering. When a target having low conductivity is used, it is preferable to apply RF sputtering or ion beam sputtering, but considering the film formation rate, it is more preferable to apply RF sputtering.
In the present embodiment, the case where the phase shift film 2 is composed of three layers of the first layer 21, the second layer 22, and the third layer 23 has been described, but the back surface reflectance R of the phase shift film 2 is determined. If the effect on the enhancing effect is small, the fourth layer may be further provided on the third layer 23. Although not particularly limited, the fourth layer may be formed of a material composed of silicon and oxygen, or a material composed of one or more elements selected from silicon and oxygen and a non-metal element and a metalloid element. preferable.

The mask blank 100 includes a light-shielding film 3 on the phase shift film 2. Generally, in a binary type transfer mask, the outer peripheral region of a region where a transfer pattern is formed (transfer pattern forming region) is transmitted through the outer peripheral region when exposure-transferred to a resist film on a semiconductor wafer using an exposure apparatus. It is required to secure an optical density (OD) equal to or higher than a predetermined value so that the resist film is not affected by the exposure light. This point is the same for the phase shift mask. Usually, in the outer peripheral region of the transfer mask including the phase shift mask, the OD is preferably 2.8 or more, and more preferably 3.0 or more. The phase shift film 2 has a function of transmitting exposure light with a predetermined transmittance T, and it is difficult to secure a predetermined value of optical density only with the phase shift film 2. Therefore, at the stage of manufacturing the mask blank 100, it is necessary to laminate the light-shielding film 3 on the phase-shift film 2 in order to secure the insufficient optical density. With such a configuration of the mask blank 100, the light-shielding film 3 in the region where the phase shift effect is used (basically the transfer pattern forming region) is removed during the manufacturing of the phase shift mask 200 (see FIG. 2). Then, the phase shift mask 200 in which the optical density of a predetermined value is secured in the outer peripheral region can be manufactured.

The light-shielding film 3 can be applied to both a single-layer structure and a laminated structure having two or more layers. Further, even if each layer of the light-shielding film 3 having a single-layer structure and the light-shielding film 3 having a laminated structure of two or more layers has substantially the same composition in the thickness direction of the film or the layer, the composition is in the thickness direction of the layer. It may have an inclined configuration.

The mask blank 100 in the form shown in FIG. 1 has a configuration in which a light-shielding film 3 is laminated on the phase shift film 2 without interposing another film. For the light-shielding film 3 in this configuration, it is necessary to apply a material having sufficient etching selectivity with respect to the etching gas used when forming a pattern on the phase shift film 2. The light-shielding film 3 in this case is preferably formed of a material containing chromium. Examples of the material containing chromium that forms the light-shielding film 3 include a material containing chromium metal and one or more elements selected from oxygen, nitrogen, carbon, boron, and fluorine in chromium.

Generally, a chromium-based material is etched with a mixed gas of a chlorine-based gas and an oxygen gas, but a chromium metal does not have a very high etching rate with respect to this etching gas. Considering the point of increasing the etching rate of the mixed gas of chlorine-based gas and oxygen gas with respect to the etching gas, the material for forming the light-shielding film 3 is one or more elements selected from oxygen, nitrogen, carbon, boron and fluorine in chromium. A material containing is preferable. Further, the chromium-containing material forming the light-shielding film 3 may contain one or more elements of molybdenum, indium and tin. By containing one or more elements of molybdenum, indium and tin, the etching rate for a mixed gas of chlorine-based gas and oxygen gas can be made faster.

Further, the light-shielding film 3 may be formed of a material containing a transition metal and silicon as long as etching selectivity for dry etching can be obtained with the material forming the third layer 23 (particularly the surface layer portion). .. This is because the material containing the transition metal and silicon has high light-shielding performance, and the thickness of the light-shielding film 3 can be reduced. Examples of the transition metal contained in the light-shielding film 3 include molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), chromium (Cr), hafnium (Hf), nickel (Ni), and vanadium (V). , Zirconium (Zr), ruthenium (Ru), rhodium (Rh), zinc (Zn), niobium (Nb), palladium (Pd) and the like, or an alloy of these metals. Examples of the metal element other than the transition metal element contained in the light-shielding film 3 include aluminum (Al), indium (In), tin (Sn) and gallium (Ga).

When the light-shielding film 3 has two layers, a structure may be provided in which a layer made of a material containing chromium and a layer made of a material containing a transition metal and silicon are laminated in this order from the phase shift film 2 side. The specific matters of the material containing chromium and the material containing transition metal and silicon in this case are the same as in the case of the light-shielding film 3 described above.

The mask blank 100 preferably has a reflectance (back surface reflectance) of 20% or more on the translucent substrate 1 side (back surface side) with respect to ArF exposure light in a state where the phase shift film 2 and the light shielding film 3 are laminated. .. When the light-shielding film 3 is made of a material containing chromium, or when the layer of the light-shielding film 3 on the phase shift film 2 side is made of a material containing chromium, the ArF exposure light incident on the light-shielding film 3 When the amount of light is large, the phenomenon that chromium is photoexcited and chromium moves to the phase shift film 2 side is likely to occur. By setting the back surface reflectance to ArF exposure light in a state where the phase shift film 2 and the light shielding film 3 are laminated to 20% or more, the movement of chromium can be suppressed. Further, when the light-shielding film 3 is made of a material containing a transition metal and silicon, if the amount of ArF exposure light incident on the light-shielding film 3 is large, the transition metal is photoexcited and the transition metal is moved to the phase shift film 2 side. The phenomenon of moving is likely to occur. By setting the back surface reflectance to ArF exposure light in a state where the phase shift film 2 and the light shielding film 3 are laminated to 20% or more, the movement of this transition metal can be suppressed.

In the mask blank 100, it is preferable that the hard mask film 4 formed of a material having etching selectivity with respect to the etching gas used when etching the light-shielding film 3 is further laminated on the light-shielding film 3. Since the hard mask film 4 is basically not limited in optical density, the thickness of the hard mask film 4 can be significantly reduced as compared with the thickness of the light-shielding film 3. The resist film made of an organic material needs to have a thickness sufficient to function as an etching mask until the dry etching for forming a pattern on the hard mask film 4 is completed. The thickness can be significantly reduced. Thinning the resist film is effective in improving the resist resolution and preventing pattern collapse, and is extremely important in meeting the demand for miniaturization.

When the light-shielding film 3 is made of a material containing chromium, the hard mask film 4 is preferably made of a material containing silicon. Since the hard mask film 4 in this case tends to have low adhesion to the resist film of the organic material, the surface of the hard mask film 4 is subjected to HMDS (Hexamethyldisilazane) treatment to improve the adhesion of the surface. Is preferable. The hard mask film 4 in this case _{is more preferably formed of SiO 2} , SiN, SiON, or the like.

Further, as the material of the hard mask film 4 when the light-shielding film 3 is made of a material containing chromium, in addition to the above, a material containing tantalum can also be applied. Examples of the material containing tantalum in this case include, in addition to tantalum metal, a material in which tantalum contains one or more elements selected from nitrogen, oxygen, boron and carbon. For example, Ta, TaN, TaO, TaON, TaBN, TaBO, TaBON, TaCN, TaCO, TaCON, TaBCN, TaBOCN and the like can be mentioned. Further, when the light-shielding film 3 is made of a material containing silicon, the hard mask film 4 is preferably formed of the above-mentioned material containing chromium.

In the mask blank 100, it is preferable that the resist film of the organic material is formed with a film thickness of 100 nm or less in contact with the surface of the hard mask film 4. In the case of a fine pattern corresponding to the DRAM hp 32 nm generation, the transfer pattern (phase shift pattern) to be formed on the hard mask film 4 may be provided with SRAF (Sub-Resolution Assist Feature) having a line width of 40 nm. However, even in this case, since the cross-sectional aspect ratio of the resist pattern can be as low as 1: 2.5, it is possible to prevent the resist pattern from collapsing or detaching during development, rinsing, or the like of the resist film. It is more preferable that the resist film has a film thickness of 80 nm or less.

FIG. 2 shows a phase shift mask 200 according to an embodiment of the present invention manufactured from the mask blank 100 of the first embodiment and a manufacturing process thereof. As shown in FIG. 2 (g), in the phase shift mask 200, the phase shift pattern 2a, which is a transfer pattern, is formed on the phase shift film 2 of the mask blank 100, and the light shielding pattern 3b is formed on the light shielding film 3. It is characterized by being. In the case where the mask blank 100 is provided with the hard mask film 4, the hard mask film 4 is removed during the process of producing the phase shift mask 200.

The method for manufacturing a phase shift mask according to an embodiment of the present invention uses the mask blank 100 described above, and includes a step of forming a transfer pattern on the light-shielding film 3 by dry etching and masking the light-shielding film 3 having the transfer pattern. It is provided with a step of forming a transfer pattern on the phase shift film 2 by dry etching and a step of forming a light-shielding pattern 3b on the light-shielding film 3 by dry etching using a resist film (resist pattern 6b) having a light-shielding pattern as a mask. It is characterized by that. Hereinafter, the method for manufacturing the phase shift mask 200 of the present invention will be described according to the manufacturing process shown in FIG. Here, a method of manufacturing the phase shift mask 200 using the mask blank 100 in which the hard mask film 4 is laminated on the light-shielding film 3 will be described. Further, a case where a material containing chromium is applied to the light-shielding film 3 and a material containing silicon is applied to the hard mask film 4 will be described.

First, a resist film is formed by a spin coating method in contact with the hard mask film 4 of the mask blank 100. Next, the first pattern, which is a transfer pattern (phase shift pattern) to be formed on the phase shift film 2, is exposed and drawn on the resist film with an electron beam, and further subjected to a predetermined process such as a development process to perform a phase shift. A first resist pattern 5a having a shift pattern was formed (see FIG. 2A). Subsequently, using the first resist pattern 5a as a mask, dry etching was performed using a fluorine-based gas to form the first pattern (hard mask pattern 4a) on the hard mask film 4 (see FIG. 2B). ..

Next, after removing the first resist pattern 5a, dry etching is performed using a mixed gas of chlorine-based gas and oxygen gas using the hard mask pattern 4a as a mask, and the first pattern (light shielding) is applied to the light shielding film 3. Pattern 3a) is formed (see FIG. 2C). Subsequently, dry etching was performed using a fluorine-based gas using the light-shielding pattern 3a as a mask to form a first pattern (phase shift pattern 2a) on the phase shift film 2 and remove the hard mask pattern 4a (FIG. 6). 2 (d)).

Next, a resist film was formed on the mask blank 100 by a spin coating method. Next, a second pattern, which is a pattern to be formed on the light-shielding film 3 (light-shielding pattern), is exposed and drawn on the resist film with an electron beam, and further subjected to a predetermined process such as development processing to have a light-shielding pattern. A second resist pattern 6b was formed (see FIG. 2E). Subsequently, using the second resist pattern 6b as a mask, dry etching was performed using a mixed gas of chlorine-based gas and oxygen gas to form a second pattern (light-shielding pattern 3b including a light-shielding band) on the light-shielding film 3. (See FIG. 2 (f)). Further, the second resist pattern 6b was removed, and a predetermined process such as cleaning was performed to obtain a phase shift mask 200 (see FIG. 2 (g)).

The chlorine-based gas used in the dry etching is not particularly limited as long as it contains Cl. For example, Cl ₂ , NaCl ₂ , CHCl ₃ , CH ₂ Cl ₂ , CCl ₄ , BCl _{3, and the} like can be mentioned. Further, the fluorine-based gas used in the dry etching is not particularly limited as long as it contains F. For example, CHF ₃ , CF ₄ , C ₂ F ₆ , C ₄ F ₈ , SF _{6, and the} like can be mentioned. In particular, the fluorine-based gas containing no C has a relatively low etching rate with respect to the glass substrate, so that damage to the glass substrate can be further reduced.

The phase shift mask 200 of the present invention is manufactured by using the above-mentioned mask blank 100. Therefore, the phase shift film 2 (phase shift pattern 2a) on which the transfer pattern is formed has a transmittance T of 15% or more with respect to the ArF exposure light, and the exposure light transmitted through the phase shift pattern 2a and the phase shift pattern 2a. The phase difference between the exposure light and the exposure light that has passed through the air for the same distance as the thickness is within the range of 150 degrees or more and 210 degrees, and the transmittance A of the ArF exposure light is 60% or less. Further, the phase shift mask 200 has a back surface reflectance R of 20% or more in the region of the phase shift pattern 2a in which the light-shielding patterns 3b are not laminated (the region on the translucent substrate 1 in which only the phase shift pattern 2a exists). It has become. As a result, the amount of ArF exposure light incident on the inside of the phase shift film 2 can be reduced, and the phase shift film is used to emit ArF exposure light from the phase shift film 2 with an amount of light corresponding to a predetermined transmittance. The amount of light converted into heat inside 2 can be reduced.

The phase shift mask 200 preferably has a back surface reflectance R of 40% or less in the region of the phase shift pattern 2a in which the light shielding patterns 3b are not laminated. When exposure transfer is performed on a transfer target (resist film on a semiconductor wafer, etc.) using the phase shift mask 200, the range in which the reflected light on the back surface side of the phase shift pattern 2a does not significantly affect the exposure transfer image. To do.

The phase shift mask 200 preferably has a back surface reflectance of 20% or more in a region on the translucent substrate 1 of the phase shift pattern 2a on which the light shielding patterns 3b are laminated. When the light-shielding pattern 3a is made of a material containing chromium, or when the layer on the phase shift pattern 2a side of the light-shielding pattern 3a is made of a material containing chromium, the chromium in the light-shielding pattern 3a is a phase shift pattern. It is possible to suppress the movement within 2a. Further, when the light-shielding pattern 3a is formed of a material containing a transition metal and silicon, it is possible to suppress the transition metal in the light-shielding pattern 3a from moving into the phase shift pattern 2a.

The method for manufacturing a semiconductor device of the present invention is characterized in that a transfer pattern is exposed and transferred to a resist film on a semiconductor substrate by using the phase shift mask 200. The phase shift pattern 2a of the phase shift mask 200 has a high backside reflectance with respect to the ArF exposure light, and the amount of light of the ArF exposure light incident on the inside of the phase shift pattern 2a is reduced. As a result, the ratio of the ArF exposure light incident on the inside of the phase shift pattern 2a is converted into heat, and the heat causes thermal expansion of the translucent substrate 1 to cause the phase shift pattern 2a to shift in position. It is sufficiently suppressed. Therefore, the phase shift mask 200 is set in the exposure apparatus, and ArF exposure light is irradiated from the translucent substrate 1 side of the phase shift mask 200 to transfer the exposure to an object to be transferred (resist film on a semiconductor wafer, etc.). Even if the steps are continued, the position accuracy of the phase shift pattern 2a is high, and the desired pattern can be continuously transferred to the transfer target with high accuracy.

Hereinafter, embodiments of the present invention will be described in more detail with reference to Examples.
(Example 1)
[Manufacturing of mask blank]
A translucent substrate 1 made of synthetic quartz glass having a main surface dimension of about 152 mm × about 152 mm and a thickness of about 6.35 mm was prepared. The translucent substrate 1 has an end face and a main surface polished to a predetermined surface roughness, and then subjected to a predetermined cleaning treatment and a drying treatment. When the optical characteristics of the translucent substrate 1 were measured, the refractive index n at the wavelength of the ArF exposure light was 1.556 and the extinction coefficient k was 0.00.

_{Next, the first layer 21 (Si 3} N ₄ film Si: N = 43 atomic%: 57 atomic%) of the phase shift film 2 made of silicon and nitrogen in contact with the surface of the translucent substrate 1 was applied at 18.9 nm. It was formed to have a film thickness _{d 1.} In the first layer 21, a translucent substrate 1 is installed in a single-wafer RF sputtering apparatus, a silicon (Si) target is used, and _{a mixed gas of krypton (Kr) gas and nitrogen (N 2} ) is used as a sputtering gas. Formed by RF sputtering. Subsequently, on the first layer 21, the second layer 22 (SiON film Si: O: N = 40 atomic%: 38 atomic%: 22 atomic%) of the phase shift film 2 composed of silicon, nitrogen and oxygen was placed 17. It was formed with a film thickness d _{2 of 6 nm.} The second layer 22 was formed by reactive sputtering (RF sputtering) using a mixed gas of argon (Ar), oxygen (O ₂ ) and nitrogen (N _{2) as a sputtering gas using a silicon (Si) target.} Then, on the second layer 22, the third layer 23 (Si ₃ N ₄ film Si: N = 43 atomic%: 57 atomic%) of the _{phase shift film 2 made of silicon and nitrogen is formed with a film thickness d 3 of 33.0 nm.} Formed in. The third layer 23 was formed by reactive sputtering (RF sputtering) using a mixed gas of krypton (Kr) and nitrogen (N _{2) as a sputtering gas using a silicon (Si) target. That is, the total film thickness d T} of the three layers of the first layer 21, the second layer 22, and the third layer 23 in the phase shift film 2 of Example 1 is 69.5 nm.
The compositions of the first layer 21, the second layer 22, and the third layer 23 are the results obtained by measurement by X-ray photoelectron spectroscopy (XPS). Hereinafter, the same applies to other membranes.

Next, the translucent substrate 1 on which the phase shift film 2 was formed was heat-treated in order to reduce the film stress of the phase shift film 2. When the transmittance T and the phase difference of the phase shift film 2 with respect to light having a wavelength of 193 nm were measured using a phase shift amount measuring device (MPM193 manufactured by Lasertec), the transmittance T was 20.7% and the phase difference was 177. It was 0.0 degrees (deg). Further, when the optical characteristics of the first layer 21, the second layer 22, and the third layer 23 of the phase shift film 2 were measured, the first layer 21 had a refractive index n ₁ of 2.61 and an extinction coefficient k _1. The second layer 22 has a refractive index n ₂ of 1.90 and an extinction coefficient k ₂ of 0.035, and the third layer 23 has a refractive index n ₃ of 2.61 and an extinction coefficient of 0.035. k ₃ was 0.36. _{The film thickness ratio d 1} / d ₃ of the first layer 21 and the third layer 23 in Example 1 was 0.573. Further, the film thickness ratio d ₂ / d _{T of the film thickness d 2} of the second layer 22 _{and the total film thickness d T of} the three layers from the first layer 21 to the third layer 23 in Example 1 is 0.253. Met. The backside reflectance (reflectance on the translucent substrate 1 side) R of the phase shift film 2 with respect to light having a wavelength of 193 nm was 20.8%, and the absorption rate A of ArF exposure light was 58.5%. ..
_{As described above, the phase shift film 2 in the first embodiment has n 1} > n when the refractive indexes of the first layer 21, the second layer 22, and the third layer 23 are n ₁ , n ₂ , and n _{3, respectively. When} the relationship of 2 and n ₂ <n ₃ is satisfied, and the extinction coefficients of the first layer 21, the second layer 22, and the third layer 23 are k ₁ , k ₂ , and k ₃ , respectively, k ₁ > k. _When the relationship of 2 and k ₂ <k ₃ is satisfied and the film thicknesses of the first layer 21 and the third layer 23 are d ₁ and d ₃ , respectively, the relationship of 0.5 ≦ d ₁ / d ₃ <1 is established. It meets. Further, when the film thickness of the second layer 22 is d ₂ , and the total film thickness of the three layers of the first layer 21, the second layer 22 and the third layer 23 is d _T , 0.24 ≦ d ₂ / d. _It satisfies the relationship of T ≤ 0.3. The phase shift film 2 in the first embodiment has a predetermined phase difference (150 degrees or more and 210 degrees or less) and optical characteristics of a transmittance of 15% or more so that a sufficient phase shift effect can be obtained, and is 60% or less. It satisfies the absorption rate A.

Next, a translucent substrate 1 on which the phase shift film 2 is formed is installed in a single-wafer DC sputtering apparatus, and an argon (Ar), carbon dioxide (CO ₂ ), and helium (C) are used using a chromium (Cr) target. A light-shielding film 3 (CrOC film Cr: O: C = 56 atoms%: 27 atoms%: 17 atoms) made of CrOC on the phase shift film 2 by reactive sputtering (DC sputtering) using a mixed gas of He) as a sputtering gas. %) With a thickness of 56 nm. The optical density (OD) of the laminated structure of the phase shift film 2 and the light-shielding film 3 with respect to light having a wavelength of 193 nm was measured and found to be 3.0 or more. Further, another translucent substrate 1 was prepared, only the light-shielding film 3 was formed under the same film-forming conditions, and the optical characteristics of the light-shielding film 3 were measured. As a result, the refractive index n was 1.95 and the extinction coefficient. k was 1.42.

Next, a translucent substrate 1 in which a phase shift film 2 and a light-shielding film 3 are laminated is installed in a single-wafer RF sputtering apparatus, and an argon (Ar) gas is sputtered using a _{silicon dioxide (SiO 2) target.} A hard mask film 4 made of silicon and oxygen was formed with a thickness of 12 nm on the light-shielding film 3 by RF sputtering as a gas. Through the above procedure, a mask blank 100 having a structure in which a phase shift film 2 having a three-layer structure, a light-shielding film 3 and a hard mask film 4 are laminated on a translucent substrate 1 is manufactured.

[Manufacturing of phase shift mask]
Next, using the mask blank 100 of Example 1, the phase shift mask 200 of Example 1 was produced by the following procedure. First, the surface of the hard mask film 4 was subjected to HMDS treatment. Subsequently, a resist film made of a chemically amplified resist for electron beam writing was formed with a film thickness of 80 nm in contact with the surface of the hard mask film 4 by a spin coating method. Next, a first pattern, which is a phase shift pattern to be formed on the phase shift film 2, is electron-beam-drawn on the resist film, subjected to a predetermined development process and a cleaning process, and has the first pattern. The resist pattern 5a of No. 1 was formed (see FIG. 2A).

Next, using the first resist pattern 5a as a mask, _{dry etching was performed using CF 4} gas to form the first pattern (hard mask pattern 4a) on the hard mask film 4 (see FIG. 2B). .. Then, the first resist pattern 5a was removed.

Subsequently, using the hard mask pattern 4a as a mask, _{dry etching is performed using a mixed gas of chlorine and oxygen (gas flow ratio Cl 2} : O ₂ = 10: 1), and the first pattern (light-shielding pattern) is applied to the light-shielding film 3. 3a) was formed (see FIG. 2C). Next, using the light-shielding pattern 3a as a mask, _{dry etching is performed using a fluorine-based gas (SF 6} + He) to form a first pattern (phase shift pattern 2a) on the phase shift film 2, and at the same time, a hard mask pattern. 4a was removed (see FIG. 2D).

Next, a resist film made of a chemically amplified resist for electron beam writing was formed on the light-shielding pattern 3a by a spin coating method with a film thickness of 150 nm. Next, a second pattern, which is a pattern to be formed on the light-shielding film (light-shielding pattern), is exposed and drawn on the resist film, and a predetermined process such as development processing is further performed to perform a predetermined process such as development processing, and the second resist having the light-shielding pattern Pattern 6b was formed (see FIG. 2E). Subsequently, using the second resist pattern 6b as a mask, _{dry etching is performed using a mixed gas of chlorine and oxygen (gas flow rate ratio Cl 2} : O ₂ = 4: 1), and the light-shielding film 3 is subjected to the second pattern (gas flow rate ratio Cl 2: O 2 = 4: 1). A light-shielding pattern 3b) was formed (see FIG. 2 (f)). Further, the second resist pattern 6b was removed, and a predetermined process such as cleaning was performed to obtain a phase shift mask 200 (see FIG. 2 (g)).

The prepared halftone type phase shift mask 200 of Example 1 is set on the mask stage of an exposure apparatus using an ArF excimer laser as exposure light, and ArF exposure light is irradiated from the translucent substrate 1 side of the phase shift mask 200. , The pattern was exposed and transferred to the resist film on the semiconductor device. A resist film after exposure transfer was subjected to a predetermined treatment to form a resist pattern, and the resist pattern was observed with an SEM (Scanning Electron Microscope). As a result, the amount of misalignment from the design pattern was within the permissible range in the plane. From this result, it can be said that the circuit pattern can be formed on the semiconductor device with high accuracy by using this resist pattern as a mask.

(Example 2)
[Manufacturing of mask blank]
The mask blank 100 of Example 2 was manufactured in the same procedure as in Example 1 except for the phase shift film 2. The phase shift film 2 of the second embodiment is the phase shift film 2 of the first embodiment in that the film thicknesses d ₁ , d ₂ , and d ₃ of the first layer 21, the second layer 22, and the third layer 23 are changed, respectively. Different from 2. Specifically, in the same manner as in Example 1, in contact with the surface of the light transmitting substrate 1 to form a first layer 21 of the phase shift film 2 with a thickness d ₁ of 24.4Nm, the second layer 22 Was formed with a film thickness d ₂ of 21.4 nm, and the third layer 23 was formed with a _{film thickness d 3 of 27 nm. That is, the total film thickness d T} of the first layer 21, the second layer 22, and the third layer 23 in the phase shift film 2 of Example 2 is 72.8 nm.

Further, the phase shift film 2 of Example 2 was also heat-treated under the same treatment conditions as in Example 1. When the transmittance and phase difference of the phase shift film 2 with respect to light having a wavelength of 193 nm were measured using a phase shift amount measuring device (MPM193 manufactured by Lasertec), the transmittance was 20.7% and the phase difference was 177.2. It was a degree (deg). Further, when the optical characteristics (refractive index and extinction coefficient) of the first layer 21, the second layer 22, and the third layer 23 of the phase shift film 2 were measured, they were all the same as those in the first embodiment. It was. _{The film thickness ratio d 1} / d ₃ of the first layer 21 and the third layer 23 in Example 2 was 0.904. Further, the thickness ratio _d 2 / _{d T} between the total thickness _{d T} of the three layers of the third layer 23 from the film thickness _{d 2} of the first layer 21 of the second layer 22 in Example 2, 0.294 Met. The backside reflectance (reflectance on the translucent substrate 1 side) R of the phase shift film 2 with respect to light having a wavelength of 193 nm was 20.3%, and the absorption rate A of ArF exposure light was 59.0%. ..

_{As described above, the phase shift film 2 in the second embodiment has n 1} > n when the refractive indexes of the first layer 21, the second layer 22, and the third layer 23 are n ₁ , n ₂ , and n _{3, respectively. When} the relationship of 2 and n ₂ <n ₃ is satisfied, and the extinction coefficients of the first layer 21, the second layer 22, and the third layer 23 are k ₁ , k ₂ , and k ₃ , respectively, k ₁ > k. _When the relationship of 2 and k ₂ <k ₃ is satisfied and the film thicknesses of the first layer 21 and the third layer 23 are d ₁ and d ₃ , respectively, the relationship of 0.5 ≦ d ₁ / d ₃ <1 is established. It meets. Further, when the film thickness of the second layer 22 is d ₂ , and the total film thickness of the three layers of the first layer 21, the second layer 22 and the third layer 23 is d _T , 0.24 ≦ d ₂ / d. _It satisfies the relationship of T ≤ 0.3. The phase shift film 2 in the second embodiment has a predetermined phase difference (150 degrees or more and 210 degrees or less) and optical characteristics of a transmittance of 15% or more so that a sufficient phase shift effect can be obtained, and is 60% or less. It satisfies the absorption rate A.
Then, the light-shielding film 3 and the hard mask film 4 were formed on the phase shift film 2 in the same procedure as in Example 1 to manufacture the mask blank 100 of Example 2. The optical density (OD) of the laminated structure of the phase shift film 2 and the light-shielding film 3 with respect to light having a wavelength of 193 nm was measured and found to be 3.0 or more.

[Manufacturing of phase shift mask]
Next, using the mask blank 100 of Example 2, the phase shift mask 200 of Example 2 was produced in the same procedure as in Example 1.

The prepared halftone type phase shift mask 200 of Example 2 is set on the mask stage of an exposure apparatus using an ArF excimer laser as exposure light, and ArF exposure light is irradiated from the translucent substrate 1 side of the phase shift mask 200. , The pattern was exposed and transferred to the resist film on the semiconductor device. A resist film after exposure transfer was subjected to a predetermined treatment to form a resist pattern, and the resist pattern was observed with an SEM (Scanning Electron Microscope). As a result, the amount of misalignment from the design pattern was within the permissible range in the plane. From this result, it can be said that the circuit pattern can be formed on the semiconductor device with high accuracy by using this resist pattern as a mask.

(Comparative Example 1)
[Manufacturing of mask blank]
The mask blank of Comparative Example 1 was manufactured in the same procedure as in Example 1 except for the phase shift film. The phase shift film of Comparative Example 1 is different from the phase shift film 2 of Example 1 in that the film thicknesses d ₁ , d ₂ , and d ₃ of the first layer, the second layer, and the third layer are changed. different. Specifically, in the same manner as in Example 1, in contact with the surface of the transparent substrate to form a first layer of phase shift film with 32nm of the film thickness d _1, film 25.4nm a second layer It is formed to a thickness _{d 2,} and the third layer is formed to a thickness _{d 3} of 15 nm. _{That is, the total film thickness d T} of the first layer, the second layer, and the third layer in the phase shift film of Comparative Example 1 is 72.4 nm.

Further, the phase shift film of Comparative Example 1 was also heat-treated under the same treatment conditions as in Example 1. When the transmittance and phase difference of the phase shift film with respect to light having a wavelength of 193 nm were measured using a phase shift amount measuring device (MPM193 manufactured by Lasertec), the transmittance was 20.7% and the phase difference was 176.9 degrees. It was (deg). Further, when the optical characteristics (refractive index and extinction coefficient) of the first layer, the second layer, and the third layer of the phase shift film were measured, they were all the same as those in Example 1. _{The film thickness ratio d 1} / d ₃ of the first layer and the third layer in Comparative Example 1 was 2.133. The thickness ratio _d 2 / _{d T} between the total thickness _{d T} of the three layers of the third layer from the second layer thickness _{d 2} of the first layer of the Comparative Example 1 was 0.351 .. The backside reflectance (reflectance on the translucent substrate side) R of the phase shift film with respect to light having a wavelength of 193 nm was 8.7%, and the absorption rate A of ArF exposure light was 70.6%.
_{As described above, the phase shift film in Comparative Example 1 has n 1} > n ₂ and n ₂ when the refractive indexes of the first layer, the second layer, and the third layer are n ₁ , n ₂ , and n _{3, respectively.} When the relationship of <n ₃ is satisfied and the extinction coefficients of the first layer, the second layer, and the third layer are k ₁ , k ₂ , and k ₃ , respectively, k ₁ > k ₂ and k ₂ <k ₃ It satisfies the relationship of. However, when the film thicknesses of the first layer and the third layer are d ₁ and d ₃ , respectively, the relationship of 0.5 ≦ d ₁ / d ₃ <1 is not satisfied. Further, when the film thickness of the second layer is d ₂ , and the total film thickness of the three layers of the first layer, the second layer, and the third layer is d _T , 0.24 ≤ d ₂ / d _T ≤ 0. It does not satisfy the relationship of 3. The phase shift film in Comparative Example 1 has a predetermined phase difference (150 degrees or more and 210 degrees or less) and optical characteristics of a transmittance of 15% or more so that a sufficient phase shift effect can be obtained, but is 60%. It does not satisfy the following absorption rate A.

Through the above procedure, a mask blank of Comparative Example 1 having a structure in which a phase shift film, a light-shielding film, and a hard mask film were laminated on a translucent substrate was manufactured. The optical density (OD) of the laminated structure of the phase shift film and the light-shielding film with respect to light having a wavelength of 193 nm was measured and found to be 3.0 or more.

[Manufacturing of phase shift mask]
Next, using the mask blank of Comparative Example 1, a phase shift mask of Comparative Example 1 was produced in the same procedure as in Example 1.

The produced halftone type phase shift mask of Comparative Example 1 is set on the mask stage of an exposure apparatus using an ArF excimer laser as exposure light, and ArF exposure light is irradiated from the translucent substrate side of the phase shift mask to form a semiconductor device. The pattern was exposed and transferred to the upper resist film. A resist film after exposure transfer was subjected to a predetermined treatment to form a resist pattern, and the resist pattern was observed with an SEM (Scanning Electron Microscope). As a result, the amount of misalignment from the design pattern was large, and many places were found that were out of the permissible range. From this result, it is expected that a disconnection or a short circuit will occur in the circuit pattern formed on the semiconductor device using this resist pattern as a mask.

1 Translucent substrate 2 Phase shift film 21 First layer 22 Second layer 23 Third layer 2a Phase shift pattern 3 Light-shielding film 3a, 3b Light-shielding pattern 4 Hard mask film 4a Hard mask pattern 5a First resist pattern 6b Second Resist pattern 100 mask blank 200 phase shift mask

Claims (20)

A mask blank having a phase shift film on a translucent substrate.
The phase shift film has a function of transmitting the exposure light of the ArF excimer laser with a transmittance of 15% or more, and the exposure light transmitted through the phase shift film in the air by the same distance as the thickness of the phase shift film. It has a function of causing a phase difference of 150 degrees or more and 210 degrees or less with the exposure light that has passed through.
The phase shift film is formed of a material containing a non-metal element and silicon.
The phase shift film includes a structure in which a first layer, a second layer, and a third layer are laminated in this order from the translucent substrate side.
When the refractive indexes of the first layer, the second layer, and the third layer at the wavelength of the exposure light are n ₁ , n ₂ , and n ₃ , respectively, the relationship of n ₁ > n ₂ and n ₂ <n _3. The filling,
When the extinction coefficients of the first layer, the second layer, and the third layer at the wavelength of the exposure light are k ₁ , k ₂ , and k ₃ , respectively, k ₁ > k ₂ and k ₂ <k ₃ . Meet the relationship,
A mask blank characterized in that the relationship of 0.5 ≦ d ₁ / d ₃ <1 is satisfied when the film thicknesses of the first layer and the third layer are d ₁ and d _{3, respectively.} When the film thickness of the second layer is d ₂ , and the total film thickness of the three layers of the first layer, the second layer, and the third layer is d _T , 0.24 ≦ d ₂ / d _T ≦ The mask blank according to claim 1, wherein the mask blank satisfies the relationship of 0.3. The mask blank according to claim 1 or 2, wherein the first layer has a refractive index n ₁ of 2.3 or more and an extinction coefficient k _{1 of 0.2 or more.} The mask according to any one of claims 1 to 3, wherein the second layer has a refractive index n ₂ of 1.7 or more and an extinction coefficient k _{2 of 0.01 or more.} blank. The mask according to any one of claims 1 to 4, wherein the third layer has a refractive index n ₃ of 2.3 or more and an extinction coefficient k _{3 of 0.2 or more.} blank. The aspect according to any one of claims 1 to 5, wherein the phase shift film is formed of a material composed of a non-metal element and silicon, or a material composed of a metalloid element, a non-metal element and silicon. Mask blank. The mask blank according to any one of claims 1 to 6, wherein the first layer, the second layer, and the third layer are all made of a material containing nitrogen. The mask blank according to any one of claims 1 to 7, wherein the second layer is made of a material containing oxygen. The mask blank according to any one of claims 1 to 8, wherein a light-shielding film is provided on the phase shift film. A phase shift mask provided with a phase shift film having a transfer pattern on a translucent substrate.
The phase shift film has a function of transmitting the exposure light of the ArF excimer laser with a transmittance of 15% or more, and the exposure light transmitted through the phase shift film in the air by the same distance as the thickness of the phase shift film. It has a function of causing a phase difference of 150 degrees or more and 210 degrees or less with the exposure light that has passed through.
The phase shift film is formed of a material containing a non-metal element and silicon.
The phase shift film includes a structure in which a first layer, a second layer, and a third layer are laminated in this order from the translucent substrate side.
When the refractive indexes of the first layer, the second layer, and the third layer at the wavelength of the exposure light are n ₁ , n ₂ , and n ₃ , respectively, the relationship of n ₁ > n ₂ and n ₂ <n _3. The filling,
When the extinction coefficients of the first layer, the second layer, and the third layer at the wavelength of the exposure light are k ₁ , k ₂ , and k ₃ , respectively, k ₁ > k ₂ and k ₂ <k ₃ . Meet the relationship,
A phase shift mask characterized in that the relationship of 0.5 ≦ d ₁ / d ₃ <1 is satisfied when the film thicknesses of the first layer and the third layer are d ₁ and d _{3, respectively.} When the film thickness of the second layer is d ₂ , and the total film thickness of the three layers of the first layer, the second layer, and the third layer is d _T , 0.24 ≦ d ₂ / d _T ≦ The phase shift mask according to claim 10, wherein the phase shift mask satisfies the relationship of 0.3. The phase shift mask according to claim 10 or 11, wherein the first layer has a refractive index n ₁ of 2.3 or more and an extinction coefficient k _{1 of 0.2 or more.} The phase according to any one of claims 10 to 12, wherein the second layer has a refractive index n ₂ of 1.7 or more and an extinction coefficient k _{2 of 0.01 or more.} Shift mask. The phase according to any one of claims 10 to 13, wherein the third layer has a refractive index n ₃ of 2.3 or more and an extinction coefficient k _{3 of 0.2 or more.} Shift mask. The aspect according to any one of claims 10 to 14, wherein the phase shift film is formed of a material composed of a non-metal element and silicon, or a material composed of a metalloid element, a non-metal element and silicon. Phase shift mask. The phase shift mask according to any one of claims 10 to 15, wherein the first layer, the second layer, and the third layer are all made of a material containing nitrogen. The phase shift mask according to any one of claims 10 to 16, wherein the second layer is made of a material containing oxygen. The phase shift mask according to any one of claims 10 to 17, wherein a light-shielding film having a pattern including a light-shielding band is provided on the phase-shift film. A method for manufacturing a phase shift mask using the mask blank according to claim 9.
The process of forming a transfer pattern on the light-shielding film by dry etching and
A step of forming a transfer pattern on the phase shift film by dry etching using a light-shielding film having the transfer pattern as a mask, and
A method for manufacturing a phase shift mask, which comprises a step of forming a pattern including a light-shielding band on the light-shielding film by dry etching using a resist film having a pattern including a light-shielding band as a mask. A method for manufacturing a semiconductor device, which comprises a step of exposing and transferring a transfer pattern to a resist film on a semiconductor substrate using the phase shift mask according to claim 18.

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